Purpose. To construct a closed analytical expression for the two-electron exchange interaction potential, which define the charge transfer processes into the doubly excited states in collisions of the homonuclear diatomic molecules with multicharged ions.
Methods. The semiclassical method and the asymptotic version of the surface integral method have been used for construction of the asymptotically correct two-center wave function and the two-electron exchange interaction.
Results. We have constructed the semiclassical representation for the two-center electronic wave function of the quasimolecular systems, which consist of the homonuclear diatomic molecule and atomic ion, for the region of a large separation between heavy particles. The analytical expression (in terms of full elliptic integrals) of the asymptotic of a two-electron exchange interaction responsible for the formation of doubly excited ionic states has been obtained.
Conclusions. An analytical study of the asymptotic properties (at large distances between interacting particles) of the quasimolecular system that consists of an ion and a homonuclear diatomic molecule has been carried out. The new analytical expression for the leading term of the two-electron exchange interaction responsible for capture into the doubly excited states has been obtained in the framework of the semiclassical version of the asymptotic approach. It is assumed that the energies of the tunneling electron before and after the recharge process are not much different. The expressions obtained for exchange interaction can be used for the study of the two-electron transfer processes into a doubly excited state at the collision of a homonuclear diatomic molecule with an atomic ion
Keywords: slow ion-molecule collisions, charge transfer, doubly excited states, asymptotic theory